Vascular analysis is a common clinical application of image analysis technology. For example, it is known to use image analysis technology for the analysis of three-dimensional (3D) image data of a vascular structure acquired using Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) techniques. According to known techniques, identification of different branches of the vascular structure can be performed manually, for example by manually identifying the extremities of each branch. Subsequently, an algorithm is implemented, which determines the path of each branch from the 3D image data to provide quantitative 3D information for each branch. It is also known to manually label the different branches of the vascular structure.
However, manual identification and labelling of different branches of a vascular can be time-consuming and can, in particular, prevent the provision of quantitative spatial information in real-time or near real-time as may be required when performing an invasive diagnostic procedure such as a CT Angiogram (CTA) or a Magnetic Resonance Angiogram (MRA) or when performing a percutaneous intervention, for example, when performing angioplasty or when deploying a stent.
Detecting, tracking, labelling and segmentation of vascular structures and other branching structures is difficult. Known methods for automatically identifying a vascular structure in a patient generally rely upon a comparison of 3D image data of the vascular structure with 3D image data of corresponding vascular structures in other patients or upon registering a 3D image data set with a typical 3D image data set from an anatomical atlas. Some known methods of labelling a vascular structure rely upon specific tree labelling algorithms, for example based upon determining a topology of the vascular structure and then comparing the determined topology of the vascular structure with a typical topology of the vascular structure.
Tracking of vascular structures, or other branching structures can present particular difficulties when the part of the branching structure is distal from the root of the branching structure, for example terminal vessels arising from remote branching points. Such distal parts of the branching structure are usually narrower than main parts of the branching structure nearer the root, making them harder to detect and track.
The tracking and identification of such sub-branches can, nevertheless, be important, for example for inspection of vessels for pathology (for example, artherosclerosis, stenoses, aneurysms), measurement of pathology (for example, vessel diameter in the cases of stenosis) and treatment planning (for example, stent insertion, catheter access).